#### Optics Book Back Questions

10th Standard

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Science

Time : 00:45:00 Hrs
Total Marks : 30
4 x 1 = 4
1. The refractive index of four substances A, B, C and D are 1.31, 1.43, 1.33, 2.4 respectively. The speed of light is maximum in

(a)

A

(b)

B

(c)

C

(d)

D

2. Power of a lens is –4D, then its focal length is

(a)

4m

(b)

–40m

(c)

–0.25 m

(d)

–2.5 m

3. In a myopic eye, the image of the object is formed

(a)

behind the retina

(b)

on the retina

(c)

in front of the retina

(d)

on the blind spot

4. If VB, VG, VR be the velocity of blue, green and red light respectively in a glass prism, then which of the following statement gives the correct relation?

(a)

VB = VG = VR

(b)

VB > VG >VR

(c)

VB < VG < VR

(d)

VB < VG > VR

5. 4 x 1 = 4
6. The path of the light is called as_____________

()

ray

7. The refractive index of a transparent medium is always greater than__________

()

one

8. According to Rayleigh’s scattering law, the amount of scattering of light is inversely proportional to the fourth power of its____________

()

wavelength

9. Amount of light entering into the eye is controlled by________

()

Iris

10. 4 x 2 = 8
11. Draw a ray diagram to show the image formed by a convex lens when the object is placed between F and 2F.

12. Differentiate convex lens and concave lens

13. What is power of accommodation of eye?

14. Why are traffic signals red in colour?

15. 1 x 7 = 7
16. While doing an experiment for the determination of focal length of a convex lens, Raja Suddenly dropped the lens. It got broken into two halves along the axis. If he continues his experiment with the same lens,
(a) can he get the image?
(b) Is there any change in the focal length?

17. 1 x 7 = 7
18. A beam of light passing through a diverging lens of focal length 0.3m appear to be focused at a distance 0.2m behind the lens. Find the position of the object.